Foam Floatation...Is it needed?

[Russ]

I never worried about my Hunter 34 sinking. However, we sailed Barnegat Bay where the average depth was 6' so it was hard to actually totally sink your boat. In fact, keeping it totally floating and not grounded was often the challenge.

I took out some flotation above the mirror. That is valuable storage space and what little flotation it afforded, I think the boat might still float if holed without it. I don't sail it as if it would float.

I've searched and searched and have not found an account of a Mac sinking to the point of flotation being engaged. I know of a Venture 23 that actually sank after a knockdown and turtling that filled the boat. Much lower freeboard , less ballast than our X/Ms. A few Macs have capsized and every account I found it was because of huge captain error and overloading. Fact is, for tens of thousands of these boats out there and so few capsizing, they are incredibly safe. Most Mac owners tend to be first time sailors and even with this, these Macs seem to escape disaster. Gotta give credit to Roger for a good, simple and safe design. I don't see the flotation being important in that aspect as much as keeping water out of the cabin in the first place.

People may say what they want about our boats, but they have an incredible safety record.

[NiceAft]

Well said.

Ray

[Wayne nicol]

hear hear

[Boblee]

Yep except for last year when we got hit with a bullet off some high cliffs trying to anchor with the boom tent up and no ballast as we were only powering have never even looked like laying ours over or even felt threatened.
As for holing it and sinking ours has more positive flotation than std but way more weight, the dinghy is always on the line out back anyway as I really don't want to be in our waters here without some protection and certainly more than a lifejacket, they have got to have a pretty enviable safety record but for newbies the tenderness till 10% could be unsettling.

[Steve K]

If sinking, you could always throw the life raft into the cabin and pull the ripcord

There used to be a company that made airbag systems for boats. They worked very similarly to what I described above.
They suddenly went out of business. Their systems used CO2 bottles for inflation. I heard they got sued after an on board bottle leaked, ending up suffocating occupants of the boat. Don't know and can't confirm this to be true though.

But......... why wouldn't a couple air bags of some kind hooked up to a scuba tank work as a nifty emergency measure
Some of you engineer types on here should work on this. I'll take a free system for the idea, if it goes commercial.
(saving this post )

SK

[mastreb]

It's entirely possible that even a relatively small pressurized CO2 bottle with a leak could entirely displace the air in a small boat cabin. One could use a nitrogen or compressed air bottle, but those bottles are expensive, hard to find, and not much in commercial use which raises costs dramatically.

I think the best bet for something like this would be the "explosive powder" air-bags used in cars, where there is no gas until the detonating component explodes and the gas is entirely contained in the bag. There would be no leaks possible, and if the bag detonates you'd know immediately, it would wake people up if they were asleep, and there's not enough gas to poison the occupants anyway.

It's a hard problem. Current systems are triggered by a calcium carbonate tablet (alka-seltzer) that dissolves in water and releases a trigger. This could be used to detonate the powder-type airbag.

But the idea that you're going to keep a keelboat afloat means that you've have to have enough of these bags to nearly fill the cabin space, which would make escape difficult. Liability looms large, because you're adopting a problem that currently nobody accepts blame for.

Not a project I would take on.

[Boblee]

Not that worried, the dinghy could be rough but with some of the boat at least above water don't think theres a real problem unless you are somewhere you really shouldn't be.

[mrron_tx]

Kadet: Some great replies for You here , but , I have a question Where did You get Your dinghy davit system ??? I've looked at several..... but really like that one. Thanks. Ron. Dauntless.

[kadet]

Kadet: Some great replies for You here , but , I have a question Where did You get Your dinghy davit system ??? I've looked at several..... but really like that one. Thanks. Ron. Dauntless.

Built them.. Stainless steel bimini tube with hardwood dowels hammered in.

[mrron_tx]

Thanks Kadet I will start gathering the tubing ...and see how big of a mess I can make Ron.

[seahouse]

My imaginary around-the-world-boat, (yeah, the one with the jettisonable keel) would have an inflatable floatation belt around its perimeter (outside) just below the belt line incorporated into a recess where the hull and deck meet, and also facilitating the attachment detail that is a frequent source of trouble on most boat designs (not just ours).

In an event, you might be wet, but alive. Would also inflate for docking, locking etc, and deflate and retract.

Meanwhile, back on planet earth...

[Three Gypsies]

I am getting ready to fit a new anchor roller etc.. and was eyeing the space below the v-berth for a V shaped water bladder. How important is these off-cuts of packing foam really?

Would 50kg of fresh water up front make the boat nose heavy or just compensate for all the cr@p I have in the rear double birth?

I don't operate too far offshore I have an EPIRB, VHF and normally have an inflatable hanging off the back davits. How many of those 6M plus Aluminium offshore fishing boats will float if flipped?

Does an really need to pretend to be a giant beanbag to be safe?

We have 40 gallons of freshwater , in bladders , in our bow . We didn't have to remove any floatation . In our 26X there is room on either side of the air pressure release valve .
We installed an electric pump and accumulator tank on the port side , under the settee , just before the galley . The fill opening is outside on the side , under the sink .
We have been happy with our setup , and it has worked well for us .
We use solar bags for bathing . The water in the bladders is for the galley .

[baldbaby2000]

Our boat sails and motors faster with more weight up front.

[dlandersson]

So if I can move my wheel pedestal up front my 300+ lbs will help my boat move faster?

Our boat sails and motors faster with more weight up front.

[mastreb]

My imaginary around-the-world-boat, (yeah, the one with the jettisonable keel) would have an inflatable floatation belt around its perimeter (outside) just below the belt line incorporated into a recess where the hull and deck meet, and also facilitating the attachment detail that is a frequent source of trouble on most boat designs (not just ours).

In an event, you might be wet, but alive. Would also inflate for docking, locking etc, and deflate and retract.

Meanwhile, back on planet earth...

I think this is a great idea, similar to the center console boats derived from RIBs where nothing inflatable is left but a beltline.

I see no downside whatsoever, nor do I see any reason why it shouldn't remain permanently inflated. It would provide emergency floatation, a bumper for docks, raft-ups, and locks, better footing for climbing over the gunnels, and a maximum heel angle that would hold below the gunnels to increase forward thrust and strongly resist capsize.

With people being used to the look of ribs, and with good design on perhaps a "tug-like" sheerline it wouldn't even look bad.